The claimed system relates to a crate-stacking system for the automatic stacking of crates, and to a crate-stacking apparatus.
Crates, for example beverage crates, are used for transporting full and empty beverage containers, such as for example bottles. A typical transport path of a crate of empties is for example as follows: a consumer returns the crate to a beverage market, and different crate types are collected at the beverage market and are collectively taken back to an empties recycling site by return transport. For the collective return transport of the crates, these are commonly stacked one on top of the other and transported on transport pallets. However, there are a large number of different crates (approximately 2000 types) which have different geometries, such that not all crate types can be stacked together. It has hitherto been the case that the stacking of the crates has been performed manually, that is to say by persons, or stacking apparatuses specific to individual crate types have been used, which commonly stack only a single crate type. However, manual stacking is laborious and time-consuming, and automatic stacking is restricted to one crate type per stacking apparatus.
A crate-stacking system for the automatic stacking of crates, optionally beverage crates, and a crate-stacking apparatus are realized which can automatically stack a multiplicity of different crates.
The expression “crate” that is used here may refer for example to beverage crates in which, for example, full or empty beverage containers, for example cans and/or bottles, can be accommodated. Furthermore, the expression “crate(s)” may refer to any type of transport aids, for example crates from the foodstuffs industry (for example E1, E2 or E3 crates), lattice boxes, trays, pallets, canisters, barrels etc.
A crate-stacking system according to an embodiment may have a multiplicity of crates (for example crates of empties) and a crate-stacking apparatus.
A crate may for example have an at least substantially rectangular outline with a longitudinal direction and a transverse/width direction and may extend perpendicular (for example in a crate-stacking direction) to said outline. A crate of said type may for example be approximately 15 cm to 45 cm wide, approximately 20 cm to 45 cm long and approximately 15 cm to 40 cm tall. The crate may optionally be 30 cm wide, 40 cm long and 30 cm tall. The crate has an upper insertion opening for the insertion of articles (for example empties). The upper insertion opening is situated opposite a base with an underside. At the underside, the crate may be equipped, at at least two opposite sides (for example the longitudinal sides, for example also all sides) with a respective, for example elongate projection (for example a contact projection or a contact edge) which extends downward from the underside and with a lateral spacing to a respectively associated outer longitudinal edge of the base. At the for example two mutually opposite sides of the crate, there may thus be provided for example a laterally outwardly open engagement longitudinal recess which is delimited by the underside of the base and by the elongate projection. For example, the engagement longitudinal recess may also be provided at all sides of the crate. That is to say, the engagement longitudinal recess has for example a rectangular cross section (height×depth) of approximately 0.5 cm to 1.5 cm by approximately 1 cm to 3 cm, optionally of approximately 1 cm by 2 cm. The rectangular cross section extends along the outer longitudinal edge, wherein the height defines an engagement height and the depth defines an engagement depth. A crate of said type can be stacked in the crate-stacking direction (for example a vertical direction, that is to say the direction of gravitational force) onto another crate. For this purpose, the elongate projection of the upper crate can engage for example into the insertion opening of a lower crate, whereby an at least substantially form-fitting connection of the two crates is realized.
The crate-stacking apparatus may have: a crate conveying apparatus, a crate lifting apparatus and a control apparatus.
The crate conveying apparatus may be provided with a conveying path (for example a conveyor belt or several parallel conveyor or chain belts, a roller conveyor, etc.) which defines a conveying surface. On the conveying surface, the crates are transportable in a conveying direction (or counter to said conveying direction, for example in the case of an alternating conveying direction). The conveying surface may have a crate feed section onto which the crates can be fed, a crate stacking section in which the crates can be stacked, and a crate discharge section, from which the stacked crates can be discharged. The crate conveying apparatus may be designed to convey the (for example individual) crates from the crate feed section to the crate stacking section and to convey the stacked crates from the crate stacking section to the crate discharge section. For example, the individual sections described above may be arranged in the stated sequence. It is also possible for the crate feed section to simultaneously be the crate discharge section.
The crate lifting apparatus may be arranged at the crate stacking section and may, on opposite sides of the conveying path, have gripping elements. For example, the crate lifting apparatus may be arranged symmetrically at both sides of the conveying path, or else may be arranged only at one side. For example, two gripping elements are arranged on each conveying path side; however, an arrangement is also possible with only one gripping element, which is for example elongate in the conveying direction, per conveying path side. Furthermore, multiple gripping elements, for example three, four, five or more per side, are also possible.
The gripping elements are for example movable toward one another and away from one another in a gripping direction at least substantially parallel to the conveying surface (for example independently of one another or synchronously with respect to one another). The gripping elements are for example driven individually or collectively in a manner coupled in terms of motion, for example by means of an electric motor or a pneumatic actuator, or the gripping elements are for example preloaded by spring force in a movement direction. Furthermore, the gripping elements are movable upward and downward synchronously in the crate-stacking direction at least substantially perpendicular to the conveying direction, for example by means of an electric motor or a pneumatic actuator. For example, said upward/downward synchronous movement is realized by means of mechanical coupling of the gripping elements at both sides of the conveying path.
Furthermore, each gripping element may have a free end with a gripping finger which projects laterally toward the conveying path and which, in the crate-stacking direction, has an engagement thickness which is at least substantially equal to or smaller than the engagement height of the engagement longitudinal recess. The engagement thickness may correspond to the engagement height for example directly adjacent to the elongate projection. The engagement thickness is for example equal to or smaller than the engagement height of the crate type with the smallest engagement height. The crate can thus be grippable at mutually opposite sides (for example the longitudinal sides or the face sides oriented transversely with respect thereto) by the gripping fingers by virtue of the gripping fingers engaging, at the mutually opposite sides, into the associated engagement longitudinal recesses. Thus, the different crate types can be stacked by means of a crate-stacking apparatus independently of further geometrical features of the crate (for example height, any projections, engagement openings etc.).
The control apparatus may be connected to the crate conveying apparatus and to the crate lifting apparatus and may have a sensor (for example a camera, a laser scanner etc.) which detects a type of the crate and/or a position of the crate in the crate stacking section. The control apparatus may furthermore be designed to control the crate conveying apparatus and the crate lifting apparatus in a manner coordinated with one another such that a process can be repeatedly performed in which:                a crate situated in the crate stacking section on the conveying surface can be gripped, for example at the two longitudinal sides, and lifted by the gripping elements,        a new crate is conveyed into the crate stacking section below the lifted crate,        the lifted crate is set down onto the new crate, and the stacked crates are transported out of the crate stacking section, or        the new crate is in turn gripped by the gripping elements and lifted together with the one or more previous crates set down thereon,        a further crate is conveyed into the crate stacking section, onto which crate the lifted crates are then set down, and        the stacked crates are transported out of the crate stacking section.        
In this way, it is possible for multiple, for example two, three, four, five and more crates to be stacked one on top of the other.
Each of the gripping elements may have a lateral abutment shoulder which is formed with a shoulder spacing, in the movement direction of the gripping element, to a free end of the associated gripping finger. For example, the abutment shoulder may also be formed as a projection which projects at the top side of the gripping element. The shoulder spacing may be smaller than the lateral engagement depth of the engagement longitudinal recess, such that, when the respective gripping finger engages into the associated engagement longitudinal recess, the abutment shoulder is in abutting contact with a side surface (for example a longitudinal or face side surface) of the crate. The crate can thus be securely gripped by means of the contact of the abutment shoulder against the side surface of the crate, and lifted by means of the gripping finger, which is in contact with the underside of the base.
At each side of the conveying path, there may be provided a single gripping element with a single gripping finger, which is for example of elongate form in the direction of the conveying path. For example, the gripping finger may have an elongate L shape, wherein the horizontal limb of the L shape makes contact with the base of the crate, and the vertical limb of the L shape forms the abutment shoulder and makes contact with the side surface of the crate.
The movement of the gripping elements toward one another and away from one another may be a pivoting movement about a spindle which is either at least substantially perpendicular or parallel to the conveying surface. Furthermore, said movement may also be realized as a linear movement. For example, in the case of a horizontal pivot spindle, the crate can be gripped at its longitudinal sides. However, for example in the case of a vertical pivot spindle by means of which the gripping elements are pivoted to the face sides of the crate from the side, the crate can be gripped at its face sides.
The movement of the gripping elements toward one another and away from one another may be controllable independently by the control apparatus, for example in order for the crate to be selectively contacted, and aligned on the conveying surface, by means of the gripping fingers in the crate stacking section before the lifting process. However, it is also possible for the gripping elements to be, for example, mechanically coupled to one another or to be controlled by the control apparatus so as to perform their movements synchronously with respect to one another.
The crate lifting apparatus may have, at the opposite sides of the conveying path, one or more centering elements (for example centering levers or panels). The centering elements are for example movable toward one another and away from one another in a centering direction, for example at least substantially parallel to the conveying surface. The centering elements are for example driven individually or collectively, for example by means of an electric motor or a pneumatic actuator. Each centering element may have an upper centering section and a lower centering section, which are each oriented laterally with respect to the conveying path. The centering sections serve, for the centering of the previous (for example lifted) crate/crates with respect to a new crate (for example a crate standing in the crate stacking section), to be able to laterally make contact with a respectively associated side surface of the previous crates/crates and a respectively associated side surface of the new crate. It is thus possible to realize reliable insertion of the projection of the upper crate into the insertion opening of the lower crate.
The centering elements may be mechanically coupled in terms of motion to the gripping elements in order to mechanically synchronize the movement of the centering elements with the movement of the gripping elements. However, such a synchronous movement may also be realized through corresponding control of the individual centering elements by the control apparatus.
The crate feed section may also be the crate discharge section. It is consequently possible for individual crates and crate stacks to be led into/out of the crate stacking section via the same section. The crate feed section and the crate discharge section may for example also be arranged, with respect to the crate lifting apparatus, such that the crates are conveyed into the crate lifting apparatus at one side by means of the crate feed section, are stacked in the crate stacking section or pass through said crate stacking section without stacking, and are discharged at the other side of the crate lifting apparatus by means of the crate discharge section.
The conveying path may have a conveying path main section and multiple crate stacking sections which are arranged laterally adjacent to the conveying path main section. Here, the crate feed section of a respective crate stacking section is for example also the crate discharge section, and may overlap the conveying path main section. The conveying path may for example be formed from different types of conveying paths, for example roller conveyors, conveyor belts, chain belt conveyors, etc., which may have different angles relative to one another. The crate-stacking apparatus may have multiple crate lifting apparatuses which are respectively assigned to the crate stacking sections.
For example, two crate stacking sections are arranged on mutually opposite sides of the conveying path main section. Such an arrangement may for example occupy a footprint which corresponds for example at least substantially to the dimensions of a Euro pallet (1200×800 mm). Furthermore, the footprint may also be for example at least substantially 1400×800 mm.
A crate-stacking apparatus for the automatic stacking of crates according to an embodiment may have a crate conveying apparatus, a crate lifting apparatus and a control apparatus. For this purpose, the crate conveying apparatus, the crate lifting apparatus and the control apparatus may be designed as described above.
Embodiments of the invention are illustrated in the figures and will be discussed in more detail below.